Remote tuning system for radio receivers



July 28, 1936. H. BAUER l 2,048,772

REMOTE TUNING' SYSTEM FOR RADIO RECEIVERS Filed sept. e, 1935 Y i mgl'.

Y INVENTOR:

am' Bauer fon/w3 fa 30 Y 'I his carrier. 4wave Patented July 28, 1936 UNrrEn STATES REMOTE4 TUNING SYSTEMfFORARADIQ.. l

RECEIVERSV Hans Bauer, New York, N.. Y...

Application `September 6, 1935s,' Serial'No.A 39,48 l

6 Claims.

`-Tln's.invention relates toa remote tuning sys-- temvforradio receivers, and more particularly to for.th e control thereof from a remote point'.

'It is the object Vof my invention to provide a remote tuning unit which maybe connected to anV existing radio-receiver installation in a most simple manner without modifying any connections other than the mere attachment of the lead from the tuning unit to any point of the lead-in from the receiving antenna to the radio-receiver. It isa further object of my invention to provide a compact tuning circuit to which the incoming broadcast energy is shunted, at which point itis mixed witha local source of oscillations to obtain^ afcarrier wave of a predetermined frequency. preferably beyondA the normal -broadcast range,` to .whichhthe radio-receiver is permanently tuned. with the signal-energy there-- on, obtained by the concomitant operation of thev local oscillator-withethe tuning circuit for the 'incoming broadcast energy, is conducted to" the radio-receiver for the-demodulation ofthe sign-alsthererom., Y y -Y Y' Y- My invention contemplates a novel form of acoup ing radio-frequency transformer composed oithree` windings wherein the primary winding the incomingbroadcast energy serves at the same. time as the secondary winding for timeoutput ,energy fromthe mixer circuit whence it isconducted tothe radio-receiver, .e Itis a further object ofmy invention to*y provide -a self-contained tuning unit remote fromrthe radio-receiver which maybe energized fromany ommercialsource of electric energy. Other objects and purposes` will appear from a more-.detailed description ofonefpreferredembodimentoi theV invention following hereinafter; takenin-conjunction with theaccompanying drawing, ,wherein, 4...Fig 1 is a diagrammatir application of theinvention, eilig.v 2pisfa circuit diagram of the remote tun-y ingfunitpand f ,Fige 3 is -afront eleva`tior1-with certain parts in sectionfof thenovel coupling transformer form'- ing part/of"- my invention.

Inelligel is shownV any conventional'type-of radio-receiver'which is permanently tuned' toa predetermined frequency', preferably beyond the normalbroadcastband. In the legend applied tor'Figgl, the 'receiver is shown tuned below the lower end ofthe broadcast band; 'at'. a frequency view of the general4 of25.k. ce; onnectionsare shown. from the terminals fv'th'ereceiver to the ground G and thelleadein" A' fromthe signal receivingvmeans.

The lead- Bfirom. the. remotely .situatedtele.. tuner T is connectedl to any point along the leadin. A. The plug M is plugged into -anycommercial. uowcitmainlor. electric energy.,y either A. C,

or DQ.Cglfonenergizing thefrenote tuning unit.

The .incoming. broadcast. energy is shunted from the radiol-rcei-veralong,the lead BV which is connected tothe 'primaryfwinding Ll Vof the radiofrequencytransfolmenha ingfLZf-or: its secondary winding.'` `Th'e'selec l Qof. thencoming energy is eiected byv ad'justir'ig' condenser `C L, having associated therewith the trimming; condenser C4. A...C0mpa0f1mit,is. Qbtanelbyusig a Single tube.. for rvejga'mpletype BA1, for performing all ofthe desired functions The energy'required for operatingtljiis tubegis derived" Vfrom the power I nailr'by thiec'onhgiwn fthefplus M thereto.; A rectifier'tube, type `31, l

taining thenccessarv direct current potentials requiredby'thepentagrid converter BA1. Upon the closing ofswitch I2, a circuit-)gis completed from one side of thejline through resistor 14, heaters may be. utilized for obfl-' I5 and! 6 offtheRt-wo tubes, andfuse I3 to the other side of the line Resistor Mlimits the current value throughrthe heatersto the required 0.3 ampere; 'Il'ie enrgywhich'may be rectied byl tube 3T' is filtered by a condenser-input type filter and' is` imposed` as direct current energy at the buswiles'l 8j and I9. Conductor 3U`leads from `I8 and is,conn'ected through the winding L5 and conductor 3l to the plateof' EAT. vThe second gridof the tube is connected tolead 2 2 and functions as the pl'atejof the local oscillator. Lead common p oint.. ata 4potential lower thantheplate by the voltage drop in resistor 32.

Resistor 2 5 biases theoscillatorgrid, and the resistor; 6"' biases the modulator grid. In conjunction with the latter there is a variable potentiometerresistance P associatvedas well with the transformer Ll-l-LZ, which is used for controlling the gainof l'thetu'nin'g device and' conseimpressing theN In operation, for the given example, the local oscillator must be tuned 525 k. c. higher than the modulator. Thus if reception of a station at '700 k. c. is desired, L2 and CI must be tuned to '700 k. c. and the local oscillating circuit, L4 and C2, to 1225 k. c. producing a beat frequency equivalent to the diierence between these frequencies.

Fig. 3 shows the physical arrangement of coils LI, L2 and L5 .shown schematically in Fig. 2. The incoming broadcast energy arrives over'wire B to primary winding LI which is coupled to the secondary winding L2, forming part of the; incoming modulating circuit. The output circuitI associated with the plate'of 6A1, composed of C5 and L5, is tuned to the frequency ofthe radio-receiver, and the coil L5 operatesf'as a primary winding for the secondary LI to return .the

signal energy upon a carrier wavevv of said last# mentioned frequency over the wire B tothe radio-,fi

receiver. Y i Y,

The tele-tuner `may `ber-completely shielded as indicated in dotted lines in Fig. 2." Byepass condensers are providedl at suitablev points tol ob- 1 tain desired resultsin 4a manner well known in the art.

While I have describedrm'y Vinvention* asY emsaid signal receiving means through theV inter--V mediary of a single transmission conductor, Vsaidy control means including 'a frequency converter device and said device" co prising aunitary thermionic tube'having a plurality of Avgrids, means connected to two`of s'aid gridsv for .generating a local source of oscillatior'isff variable frequency," a radio-frequency transformer for incoming" broadcast'-i 'energyl upon anotherv one fof "said grids., composed of a primary winding connectedtofsaidfsignal' receiving means and a secondary v'rinding con'- nected to said lastfmen'tioned'" grid, an' output:

1 circuit connected withsaid tube andadapted to have produced therein the resultant ofthe local source of oscillations with the@ incoming Lbroadcast energy tuned to said predeterminedfrequen cy, said output circuit including a high frequency transformer having forl its secondary winding the primary winding of said first-mentioned transformer, said last-mentioned winding-being connected to said radio .receiver .through -the -interme'diary of saidftransmi'ssion conductor, said transmissionconductor being aperiodic whereby to conduct efficiently the incoming `broadcast energy in onedirection and the signalenergy. at said predetermined frequencyinthe oppositev direction. .I 3

2. In .combination with a radio receiver tuned to a predetermined frequency beyond'the broad- 'castv range,.signal receiving, means for the incoming broadcast energy; connected with said radio receiver, Vreadily portablecontrol Vmeans i remote from said radio receiver -connectedwith Vvariable frequency,

said signal receiving means over a single transmission conductor adapted to transmit the incoming broadcast energy in one direction and the signal energy superposed upon a carrier wave of said predetermined frequency in the opposite direction, said portable control means including a frequency converter device, said device comprising a unitary thermionic tube having an electron-emitting element, a plurality of Vgrids and a plate, meansassociated with two of said grids for generating a local source of oscillations of a radio-frequency transformer for impressing the incoming broadcast energy upon another one of said grids composedof a primary winding connected to said transmission conductor and a secondary winding connected to said last-mentioned grid, an output vc'rcuit Ytuned to said predetermined frequency connected with said plate having combined therein the local lsource of oscillations with the incoming broadcastV energy, said last-mentionedy circuit. embodying a` primaryy vwinding of a radio-fre? quency transformer having asa secondary winding therefor the primary winding of said first# mentioned radio-frequency-transformer and said single "transmission conductor: adapted to conduct the energy of said output circuit to said radio receiver for deriving thelsignals therefrom.

3.In` 'combination with a radio receiver tuned" tofa predetermined frequency,'signa1 receivingv means for the Vincoming broadcast energy con-1 nected fwith 'said radio receiver, control means remote* from saidl radio receiver, a;` conductor extending from between said first means and saidY receiverto said'control means, said control means including a frequencyconverter device, said device comprising means for generating a local source of oscillations' of variable frequency;

means for Vcornbinin'gthe incoming broadcast energy therewith, andan` output circuitto ob-j tain the'signal energy upon a Vcarrier wave of said` predetermined frequency, said output cir' cuit beingfconnected to said conductor for trans' mitting said last-mentioned'carrier wave to said radio receiver for the demodulation of the'slg; nals therefrom, said conductor havingl a transf mission characteristic adaptedto the eicient transmission' ofthe incoming broadcast `energy inone direction to said control means and the transmission vof the carrier wave of said predetermined Vfrequency in the opposite direction from said control means to said `radio receiver.

4. In combination-with a radio'receiver tuned toV a predeterminedV frequency, signal receiving means for the incoming broadcast energy connected with said radio receiver, c'ontrolmeans remote from said radio receiver, a conductor extending from between said rst means and vsaid receiver .to vsaid control 'means, said control means including a frequency converter device, said device comprising means forgeneratinga localsource ofv oscillations of' variable frequency, means for combining' the incoming broadcast energywith said oscillations including a radiofrequency transformer having the primary winding thereof connected to said conductor, and an output circuit to obtain the signal energy upon a carrier wave of saidpredetermined frequency embodyinga" winding operating as aprirnary winding with respect to said rst-mentioned winding which operates as a secondary winding for the carrier wave of said predetermined frequency, saidy last-mentioned winding operating to transmit said carrier wave through the inter- 0i EL mediary of said conductor to said radio receiver for the demodulation of the signals therefrom and said conductor having an aperiodic characteristic whereby to transmit efficiently the incoming broadcast energy in one direction to said control means and the carrier wave of said predetermined frequency in the opposite direction from said control means to said radio receiver.

5. In combination with a radio receiver tuned to a predetermined frequency, signal receiving means for the incoming broadcast energy connected with said radio receiver, control means remote from said radio receiver, a conductor eX- tending from between said rst means and said receiver to said control means, said control means including a frequency converter device, said device comprising means for generating a local source of oscillations of variable frequency, means for combining the incoming broadcast energy therewith including a thermionic device and a radio-frequency transformer having the primary Winding thereof connected to said conductor and the secondary winding thereof connected to said thermionic device, and an output circuit to obtain the signal energy upon a carrier Wave of said predetermined frequency embodying a winding operating as a primary winding with respect to said first-mentioned primary winding which operates as a secondary winding for the carrier wave of said predetermined frequency, said last-mentioned winding operating to transmit said carrier Wave through the intermediary of said conductor to said radio receiver for the demodulation of the signals therefrom and said conductor having an aperiodic characteristic whereby to transmit efficiently the incoming broadcast energy in one direction to said control means and the carrier wave of said predetermined frequency in the opposite direction from said control means to said radio receiver.

6. In combination with a radio receiver tuned to a predetermined frequency beyond the normal broadcast range, signal receiving means for the incoming broadcast energy connected with said radio receiver, control means for the receiver situated remotely therefrom, a conductor extending detachably from between said first means and said receiver to said control means, Said control means including a frequency converter device, said device comprising means for generating a local source of oscillations of variable frequency, means for combining the incoming broadcast energy therewith, including a radio-frequency transformer having the primary winding thereof connected to said conductor, and an output circuit to obtain the signal energy upon a carrier wave of said predetermined frequency, said output circuit including said primary winding and connected to said conductor for transmitting said last-mentioned carrier wave to said radio receiver for the derivation of the signals therefrom, and said conductor having a transmission characteristic enabling efficient transmission of the incoming broadcast energy in one direction to said control means and the transmission of the carrier wave of said predetermined frequency in the opposite direction from said control means to said radio receiver.

HANS BAUER. 

